Plant-pollinator networks, the time dimension, and conservation: a new study just published

Biella network

After rather a long gestation period, involving much re-analysis and rewriting, we’ve finally published Paolo Biella’s research from his Master’s thesis.  It’s a really neat plant-pollinator network study from mid-elevation grasslands in Italy’s Northern Apennine.  In it we have considered the way in which such networks could be analysed in relation to plant phenology (i.e. the timing of when they flower) rather than arbitrary time slices (e.g. months, weeks).  We have also discussed how this approach may inform conservation strategies in grasslands such as these.  The full citation with a link is:

Biella, P., Ollerton, J., Barcella, M. & Assini, S. (2017) Network analysis of phenological units to detect important species in plant-pollinator assemblages: can it inform conservation strategies?  Community Ecology 18: 1-10 

I’m happy to send a PDF to anyone who is interested in seeing the full study.

Here’s the abstract:

Conservation of species is often focused either only on those that are endangered, or on maximising the number recorded on species lists. However, species share space and time with others, thus interacting and building frameworks of relationships that can be unravelled by community-level network analysis. It is these relationships that ultimately drive ecosystem function via the transfer of energy and nutrients. However interactions are rarely considered in conservation planning. Network analysis can be used to detect key species (“hubs”) that play an important role in cohesiveness of networks. We applied this approach to plant-pollinator communities on two montane Northern Apennine grasslands, paying special attention to the modules and the identity of hubs. We performed season-wide sampling and then focused the network analyses on time units consistent with plant phenology. After testing for significance of modules, only some modules were found to be significantly segregated from others. Thus, networks were organized around a structured core of modules with a set of companion species that were not organized into compartments. Using a network approach we obtained a list of important plant and pollinator species, including three Network Hubs of utmost importance, and other hubs of particular biogeographical interest. By having a lot of links and high partner diversity, hubs should convey stability to networks. Due to their role in the networks, taking into account such key species when considering the management of sites could help to preserve the greatest number of interactions and thus support many other species.

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Another new garden pollinator record – Lunar Hornet Moth

Lunar Hornet Moth cropped

Following on from last week’s post about the Ashy Mining Bee, here’s yet another new record for our garden that I spotted yesterday – the Lunar Hornet Moth (Sesia bembeciformis), one of the Clearwing Moths (family Sesiidae).  It’s a fabulous example of Batesian Mimicry in which a harmless species (the moth) has evolved to resemble a more dangerous or toxic species, in this case large wasps or hornets.  I certainly had to look twice when I saw it!  

These moths do sometimes visit flowers such as umbellifers though the shot below is posed: the moth flew out of my hands as I was moving it and landed on this cultivated geranium.  The larvae feed on sallow and willow (Salix spp.) which we don’t have in the garden, but there’s lots in and around this part of the town.

Looking at the NBN Atlas account for the species I think that this may be a first record for Northampton town itself, though it is recorded out in the county.

Lunar Hornet Moth on GeraniumP1040014

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A new pollinator for our garden: the Ashy Mining Bee

Today I’ve been cracking on with the refurbishment of the old summer house at the back of the garden that previous owners have let fall into rotten disrepair, whilst Karin attends a conference in London.  The renovation has been a slow job, due to lack of time, but a lot of fun, and a good excuse to play with power tools.  In between sawing and drilling, however, I’ve been keeping an eye out for bees and other flower visitors and was delighted to spot a new species for the garden – the Ashy Mining Bee (Andrena cineraria).  It’s a beautiful and distinctive insect that I know from other sites in Northampton, but had not recorded here previously.  The record has been submitted to the BWARS recording scheme for this species.

Do look out for this bee, it’s difficult to confuse it with anything else (which is rare in Andrena….)  Here’s a few photographs of a female collecting pollen from a cultivated rose, that I took with my phone:

Ashy Mining Bee 2017-06-17 10.55.45Ashy Mining Bee 2017-06-17 10.55.53

Ashy Mining Bee 2017-06-17 10.56.10

 

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Saved by a bee: a true story, with reflections and photos from PopBio2017

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The blog has been a bit quiet of late, due to a lot of traveling on my part, starting with field work in Tenerife, then a weekend away with friends on the Isle of Wight, followed by the topic of this post: PopBio2017 – the 30th Conference of the Plant Population Biology Section of the Ecological Society of Germany, Austria and Switzerland in Halle, Germany.  And I’d like to begin with a story….

The organisers of PopBio2017 had invited me to be one of five keynote speakers at the conference and I was due to deliver a talk on “The macroecology of wind and animal pollination” first thing (09:00) on Thursday morning.  So the night before I duly set my phone’s alarm for 07:00, thinking I’d have enough time to get ready, have breakfast, then take the tram to the venue (a 15 minute ride/walk).

It was a very hot night and I left the windows open, but my mind was restless with thoughts of how to deliver the talk most effectively.  So I kept waking up during the night, and actually slept through the alarm.  The next thing I know it is 07:45 and I am being woken up by an urgent buzzing noise….from a bee!

I swear this is true: a bee had flown in through the window, buzzed for a few seconds right in front of my face, and woke me up in time to deliver my talk on pollinators!  It then turned around and flew straight back out of the window.

It actually wasn’t until I’d jumped out of bed and into the shower that I’d woken up sufficiently to appreciate what had happened…and wondered if anyone would actually believe me!  Anyway, I got to the venue with 15 minutes to spare, the talk seemed to go well, and it’s a story I think I’ll enjoy telling for some time to come.

The conference was really fabulous, with some very impressive science on show.  It was a good mix of postdocs, PhD students, and established researchers talking on a diverse range of plant ecology topics, not just “plant population biology” (whatever that really is – there was some discussion on that score).   The organisers had arranged the programme so that the keynotes in each session were followed by shorter talks broadly related to that topic, so I was followed by a series of presentations on pollination biology.  And very good they were too.

Here’s some photos from the week:

A slightly blurry audience waiting for my talk to begin (not as blurry as me after the dash to the venue however…):

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I was fascinated by the coypu that are common in the River Salle which flows through the city of Halle.  They are classed as an invasive species, but are very, very cute:

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Indeed so cute I couldn’t resist taking a selfie…

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Some interesting urban greenery including swales for flood defence:

 

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Wall plants surviving the graffiti:

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Halle’s most famous resident, Handel:

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There’s a Harry Potter feel to some parts of the town:

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The fabulous double-double-spired cathedral:

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There had to be a spiral or two, of course:

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On the Saturday after the talks had finished we took an excursion to the fascinating “Porphyry Hills” dry grasslands – unique western extensions of plant communities and species normally found in the east, including many plants of the steppe:

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These rocky outcrops have become exposed as agricultural ploughing caused the surrounding soil level to drop:

 

Some of the grassland areas have very thin soils with resultant high plant diversity:

 

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Lots in flower, though not as many pollinators as I would have liked:

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On the last evening a couple of us had a private tour of the university’s botanic garden, and well worth a visit it is too:

It was a thirsty conference – “To beer or not to beer….”?

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Finally thanks to the organisers of PopBio2017 for the invitation to speak, and to all of the conference attendees who made it such a special meeting.

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Public evening lecture on butterfly conservation – Tuesday 16th May – free and open to all

Gatekeeper cropped P1010472

The University of Northampton has recently approved the appointment of Tom Brereton as Visiting Professor in Conservation Science.  Tom is well known for his work with Butterfly Conservation, the organisation that monitors British butterfly and moth populations, and promotes their study and conservation.  However he also works with other organisations including the charity MarineLife.

The first task of any Visiting Professor is to present a public lecture on their work, which Tom is doing next Tuesday 16th May; it is entitled:

“Butterflies and other animals: 40 years of adventure in ecology and conservation”

The lecture begins at 6pm in The Grand Hall, Newton Building, St George’s Avenue, Northampton, NN2 6JD

Coffee & biscuits will be served on arrival at 5.30pm

Following the lecture there will be an opportunity for networking and discussion over drinks & nibbles.  The lecture is free and open to all; for catering purposes please advise Val Howe if you wish to attend:

Email: valerie.howe2@northampton.ac.uk
Telephone: 01604 893005

(Though if you decide to come at the last minute that’s also fine!)

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Spiral Sunday #33 – an Aeonium from Tenerife (for Karin’s birthday)

Aeonium.png

Over the past couple of weeks we’ve been extremely busy doing field work and not had great internet connections, hence no postings on the blog.  But this weekend we are staying in a lovely little hotel in a restored 18th century Canarian house in Icod de los Vinos.  So things have slowed down, though the internet is not much better.

I have managed to capture a few images of spirals along the way that I will use for upcoming Spiral Sunday posts.  As it’s Karin’s birthday today, here’s one of an Aeonium species, the group of plants that’s been the main focus of our recent field work.

Happy Birthday Karin!

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Spiral Sunday #32 – from the Guimar Badlands of Darwin’s Unrequited Isle

Guimar spiral.png

Our annual undergraduate Tenerife Field Course ends today and later I will say goodbye to the students and my University of Northampton colleagues Janet Jackson and Paul Cox: I’m staying on for another 10 days with Karin to do some additional field work.  The apartment complex where we were located had very poor wifi so I’ve not been able to post much, but we’ve moved now and I’ll try to do more in the coming week.

For Spiral Sunday this week here’s a shot of the logo for one of the protected areas that we always visit, and one of my favourite places on Tenerife: the stunning Malpais de Guimar (Guimar Badlands).

As you can see from the image below, the Guimar Badlands is a fascinating area of xerophytic scrub containing plants that are adapted to very low water levels.  It’s always the first site that we visit with the students, providing a great contrast to any habitats that they might have encountered in Britain.  A perfect introduction to Darwin’s Unrequited Isle.

Guimar 2014.png

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Spiral Sunday #31 – hola Tenerife!

Tenerife graffiti spiral P1010967.png

In a few hours I’m heading of to Tenerife with students and colleagues for our annual undergraduate field course, following which I’m staying on to be joined by Karin for a further 10 days of field work.  I’ll try to post as and when I can, though it’ll be a packed few weeks.

In the meantime this week’s Spiral Sunday is a piece of Canarian independence graffiti that I photographed a few years ago on the road above Guimar.  As I’ve mentioned before, the spiral is an ancient and important symbol in the Canary Islands.  Adios!

Tenerife graffiti spiral - full P1010968.png

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Spiral Sunday #30 – paperclips

Paperclips.png

On Wednesday I took my daughter Ellen up to Birmingham to drop off some bags and check on her flat (she’s been in California for a few weeks). Afterwards we went shopping in the city and I came across these beautiful paperclips made from flat copper wire.  They could have been especially designed for me and for Spiral (Easter) Sunday!  I couldn’t resist them and bought a bottle of 100.

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A fossilised flower in amber – with its pollinator!

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There have been only a handful of occasions in my professional life when I’ve been sent a manuscript to review that has caused my jaw to hit the floor with amazement.  The last time it occurred was July 2016 when I received a request to review a study that claimed to have found a fossil flower in amber, with an associated pollinator.  Not only that, but the flower appeared to belong to a species of asclepiad (Apocynaceae subfamily Asclepiadoideae) – the plant group on which I have focused a good deal of my attention over the years.  Even better, the study was by George Poinar, the originator of the idea to extract DNA from amber-encased fossils, thus inspiring Jurassic Park.  George is also the author of two books (Life in Amber and Quest for Life in Amber) that made a big impression on me when I was a PhD student and young post-doc*.

An asclepiad in amber?  From George Poinar?  How could I possibly refuse?!

One of the almost unique features of the asclepiads is that they disperse their pollen as discrete packages – pollinia – that attach en masse to their pollinators.  Only the unrelated orchids do anything similar, which means that identifying the pollinators of asclepiads is much more straightforward than for most plants, making them an ideal model group for studying plant-pollinator interactions.  I’ve had a deep interest in the asclepiads, and particularly their pollination ecology, for over 30 years. Over that time I’ve occasionally daydreamed that perhaps a fossil asclepiad flower in amber might be discovered in my lifetime, or an insect with a pollinarium attached, but I was amazed to see that this study had discovered both in the same piece of amber.  In the image at the top of this post, L and C point to some significant features of the flower, whilst T marks the pollinator.  And T stands for….

….a termite!  Termites are rare overall as pollinators and unknown in that role in relation to the asclepiads; P in this image points to the pollinia attached to the front of the head of the termite:

Poinar_FossilMilkweed_separate pollinia on head

You can get a better sense of the relationship between the flower and the pollinator from the photograph at the end of the this post.

After reading and re-reading and re-re-reading the manuscript I came to the conclusion that assigning the flower to a living group of asclepiads was problematical.  So (with the Editor’s permission) I solicited the views of a few colleagues with more experience than I of some of the less well-known groups of asclepiads, and related Apocynaceae s.s., the morphology of which may shed light on this intriguing fossil.  Without going into the technical details (which I’m happy to discuss with anyone who is interested) we concluded that the flower may well represent a transitional taxon as it has features of a number of different extant asclepiad lineages.  This amber, from the Dominican Republic, is estimated to be between 15 and 45 million years old, so it’s perhaps not unexpected that the set of floral features in this flower appear rather odd from a modern perspective: plants, and their flowers, evolve, just like all other organisms.

George has assigned the flower to a new genus and called it Discoflorus neotropicus  – the “different flower from the Neotropics”.  Millions of years ago this flower bloomed in the tropical forest that covered that part of the world, and attracted a worker termite to feed on its sweet nectar, pollinating the flower in the process.  Before that could take place both flower and pollinator found themselves entombed in the sticky sap being exuded by a leguminous tree called Hymenaea protera.  Many asclepiads are climbers so it’s quite possible that Discoflorus neotropicus was climbing through the branches of that tree when it got stuck.  A fateful day for flower and insect that has come down to the present day as an all-too-rare insight into ancient plant-pollinator interactions: the first fossil asclepiad flower and the first fossil asclepiad pollinator.

The study is published as follows, with a link to the journal:

Poinar Jr, G.O. (2017) Ancient termite pollinator of milkweed flowers in Dominican amber.  American Entomologist 63: 52-56

My sincere thanks to George for allowing me to highlight his research, and use his images, on my blog.  All images are (c) George O. Poinar Jr.

 

*I have a life-long interest in palaeontology that goes back to my youth, collecting fossils on the shale heaps produced from coal mining in the north of England (heaps, incidentally, that my father, grandfather, and paternal uncles had helped to create – all were coal miners in the area).  I very nearly became a professional palaeontologist but the lure of living ecosystems overcame my interest in those that are dead, though my fascination with fossils continues, particularly those in amber and (as I’ve related previously) human ancestors.

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